1、关闭lancher中搜素栏：

路径：android/packages/apps/Launcher3/src/com/android/launcher3/config/BaseFlags.java

abstract class BaseFlags {
...
    // When enabled the promise icon is visible in all apps while installation an app.
    public static final boolean LAUNCHER3_PROMISE_APPS_IN_ALL_APPS = false;

    // Enable moving the QSB on the 0th screen of the workspace
-   public static final boolean QSB_ON_FIRST_SCREEN = true;
+   public static final boolean QSB_ON_FIRST_SCREEN = false;

2、隐藏设置中的搜索栏

布局文件：android/packages/apps/Settings/res/layout/settings_homepage_container.xml

直接GONE隐藏掉，或者将导入search_bar布局删掉。

  <com.google.android.material.appbar.AppBarLayout
        android:visibility="gone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <include layout="@layout/search_bar"/>
   </com.google.android.material.appbar.AppBarLayout>

释放出搜索栏原本所占用的区域，主要将SettingsHomepageActivity.java文件中setHomepageContainerPaddingTop()方法中一级菜单距离顶部设置为searchBarMargin，以保证布局的一致性。
android/packages/apps/Settings/src/com/android/settings/homepage/SettingsHomepageActivity.java

    @VisibleForTesting
    void setHomepageContainerPaddingTop() {
        final View view = this.findViewById(R.id.homepage_container);

        final int searchBarHeight = getResources().getDimensionPixelSize(R.dimen.search_bar_height);
        final int searchBarMargin = getResources().getDimensionPixelSize(R.dimen.search_bar_margin);

        // The top padding is the height of action bar(48dp) + top/bottom margins(16dp)
        // final int paddingTop = searchBarHeight + searchBarMargin * 2;
        final int paddingTop = searchBarMargin;
        view.setPadding(0 /* left */, paddingTop, 0 /* right */, 0 /* bottom */);
    }

3、去掉全部应用界面的搜索框

布局文件-只为记录：android/packages/apps/Launcher3/res/layout/search_container_all_apps.xml

<com.android.launcher3.allapps.search.AppsSearchContainerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@id/search_container_all_apps"
    android:layout_width="match_parent"
    android:layout_height="@dimen/all_apps_search_bar_field_height"
    ...
    android:textSize="16sp"
    android:translationY="24dp" />

源码位置
android/packages/apps/Launcher3/src/com/android/launcher3/allapps/AllAppsContainerView.java

packages/apps/Launcher3/src/com/android/launcher3/allapps/AllAppsContainerView.java

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        ......
        mSearchContainer = findViewById(R.id.search_container_all_apps);
        mSearchUiManager = (SearchUiManager) mSearchContainer;
        mSearchUiManager.initialize(this);
        
        mSearchContainer.setVisibility(View.GONE); // add
}

packages/apps/Launcher3/src/com/android/launcher3/allapps/AllAppsTransitionController.java

public void setAlphas(int visibleElements, AnimationConfig config, AnimatorSetBuilder builder) {
        ......
        mAppsView.getFloatingHeaderView().setContentVisibility(hasHeaderExtra, hasAllAppsContent,  setter, headerFade, allAppsFade);
        //removed 
        //mAppsView.getSearchUiManager().setContentVisibility(visibleElements, setter, allAppsFade);

        setter.setInt(mScrimView, ScrimView.DRAG_HANDLE_ALPHA,
                (visibleElements & VERTICAL_SWIPE_INDICATOR) != 0 ? 255 : 0, allAppsFade);
}